DE 40 29 312 A describes an optical display assembly for a vehicle in which operating data is projected onto a windshield of the vehicle. The data to be displayed are selected either by an operating mode switch connected to a control assembly which is also used for the selection of the operating mode of the machine or automatically as a function of the significance of the data, in which the data is compared to pre-determined boundary values and is displayed when these boundaries are crossed. An operating mode is displayed at all times and the corresponding operating value is displayed as well.
DE 200 13 646 U proposes a computer display for a forest products or an agricultural machine in which an input is performed on an additional, relatively large membrane keyboard. The membrane keyboard may also be equipped with input keys. The data to be displayed, the input keys and the size and color of the data can be selected.
EP 1 031 263 A concerns an assembly for the adjustment of operating parameters for the control of agricultural machines. The assembly includes a control and regulating unit that is connected to an operator's terminal, sensors and actuators. With the operator's terminal an operator can provide the operating parameters of the machine as input. The operating terminal is also equipped with a display element. Various operating modes are proposed for the control and regulating unit. In addition to a so-called normal operating mode, at the first operating sequence, for example, an adjustment mode is provided in which parameters can be provided as input. In the case of a failure of the operating terminal an emergency operating mode is provided that can also be activated by means of a switch. In the emergency operating mode inputs can be provided by sensors that are normally used for the detection of operating data of the machine. The type of the displays and the possible inputs for the various modes is not specified in any further detail.
Agricultural harvesting machines, particularly combines, are relatively complex machines with a relatively high number of crop processing assemblies whose operating parameters must be adjusted to conform to the immediate harvesting conditions. The adjustments are relatively critical since they all strongly affect the results of the operation. In actual machines the adjustable crop processing assemblies are adjusted or controlled electronically by a control assembly that includes one or more microprocessors distributed over the machine. The immediate operating parameters can be recalled through display assemblies and changed by means of input devices. While experienced operators as a rule have no trouble in reading all operating parameters that are available and to change these if a change is useful, less experienced operators are frequently overwhelmed by the large number of operating parameters displayed. They also are frequently not in a position to perform meaningful inputs.